Fecal occult blood testing has become a popular, widely used procedure to detect relatively small amounts of blood in fecal specimens. This wide use and popularity arises primarily because fecal occult blood testing is non-invasive, simple and inexpensive to perform. Because the presence of fecal occult blood in a specimen is a symptom that may be associated with colon cancer or a precursor to colon cancer, fecal occult blood testing is often routinely used on a screening basis. The routine screening of patients using fecal occult blood testing has helped to detect colon cancer at a stage where the disease is readily treatable.
A popular form of fecal occult blood testing utilizes a guaiac treated test sheet upon which a specimen of fecal material is smeared. A developing solution is applied to the opposite side of the sheet, yielding a blue color suggesting blood may be present in the fecal specimen. As the need for more specific fecal occult blood tests has been recognized, the use of immunochemical testing techniques has gained popularity. As compared to a chemical test like guaiac, an immunochemical test is more specific for the detection of human hemoglobin. However, immunochemical testing is also more complicated and expensive to perform.
Regardless of the technology used in performing the fecal occult blood test, there has been an on-going need to obtain, transport and process those specimens in a manner that is as convenient and aesthetically acceptable as possible and such that the specimen is not degraded. One form of specimen collection device that has gained wide popularity is a slide formed from folded paper or cardboard. The slide includes guaiac treated paper to which the fecal specimen is applied and a cover which is closed once the specimen application is completed. A flap in the back of the slide may be opened to reveal the back of the guaiac treated paper for subsequent application of developer and observation of the paper to determine the presence of the blue color. Examples of such a test slide are disclosed in U.S. Pat. Nos. 3,996,006 and 4,365,970.
Similar approaches have been utilized in collecting specimens for use in immunochemical tests. Typically, such tests require that a substrate such as paper to which the fecal specimen has been applied must be deposited in a vial or microtiter plate. One example of collection device is a specimen slide distributed by Fujirebio, Inc. which includes a sheet of filter paper onto which the fecal specimen is applied. The cover of the slide is closed and the slide is sent to a laboratory for analysis. To remove specimen from the device for analysis, the cover of the slide is again opened, a portion of the slide carrying the filter paper is pulled away, and a pre-punched circle is removed from the filter paper for analysis. Unfortunately, the front of the Fujirebio slide must be re-opened by the medical technologist and the technologist must grasp an area inside the slide immediately adjacent the fecal smear, thus unnecessarily exposing the medical technologist to the specimen.
With the availability of both chemical and immunochemical tests, and depending on a particular patient's symptoms and risk factors, a physician may elect to perform only one of the two tests or both of the tests. The results of the two tests can complement each other since it is known that the chemical test, such as a guaiac test, detects the heme moiety of hemoglobin while the immunochemical test detects the globin moiety of human hemoglobin. With the combined tests, the probability of detecting all of the hemoglobin moieties is greatly enhanced. Thus, a convenient specimen collection device that will facilitate one or more tests from the same specimen is desirable.
Examples of sampling devices and methods of these type are disclosed in U.S. Pat. Nos. 4,645,743 and 4,789,629. These devices, however, include a separate insert to which the fecal specimen is applied by the patient. The insert is removed from the device and the insert is then punched or sectioned to obtain a portion of the insert suitable for immunological analysis. The use of such a removable insert presents a disposal problem in addition to the device itself. Also, because the insert must be punched or sectioned, additional tools must be cleaned after each use, further complicating the process and adding expense.